Medicament delivery device and method of assembling the same

ABSTRACT

The present disclosure relates to a medicament delivery device for injection of a medicament. The medicament delivery device comprising a housing having a distal end opening and a proximal end opening; a needle guard extending from the proximal end opening and moveable relative to the housing from an extended position to a retracted position in which the needle guard is biased towards the extended position. The device further comprises an activation member extending from the distal end opening and movable relative to the housing from an initial position to a final position; final position locking means arranged to restrict movement of the activation member relative to the housing when the activation member is in the final position, and needle guard locking means arranged to interact with the needle guard such that movement of the needle guard from the extended position to the retracted position is restricted when the activation member is in the final position. The present disclosure also relates to a method of assembling a medicament delivery device.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/373,099, filed Apr. 2, 2019, which is a continuation of U.S.patent application Ser. No. 14/774,877, filed Sep. 11, 2015, now U.S.Pat. No. 10,272,203, which is a U.S. National Phase Application pursuantto 35 U.S.C. §371 of International Application No. PCT/EP2014/054563filed Mar. 10, 2014, which claims priority to Swedish Patent ApplicationNo. 1350291-9, filed Mar. 12, 2013, and U.S. Provisional Application No.61/777,389, filed Mar. 12, 2013. The entire disclosure contents of theseapplications are herewith incorporated by reference into the presentapplication.

TECHNICAL FIELD

The present disclosure generally relates to a medical device and inparticular to a disposable medicament delivery device and to a method ofassembling such a device.

BACKGROUND

Parameters which normally are to be taken into account when designingdisposable medicament delivery devices include measures to render itdifficult to reuse the device and measures to protect users from needlesticks.

US2007/0191809 discloses a passive needle guard comprising a body, ashield covering the body and a spring disposed between the body and theshield. A needle can be mounted to the body at the proximal end thereof,i.e. at the end facing the user of the device during use. The body isarranged to receive a syringe for administration of a medicament. Thespring biases the shield from the proximal end of the needle guardtowards the distal end of the needle guard. A catch acts to retain theshield in the biased position. When the plunger reaches its finalposition, the thumb pad of the plunger releases the catch wherein theshield moves relative the body such that the proximal end of the bodymoves towards the distal end of the shield. The needle is thus receivedby the shield. The shield is locked in this position relative the bodyby means of a locking member which consists of a proximal end tab of thebody engaging with an inner surface slot at the distal end of theshield.

A problem with existing solutions is however that the needle is notcovered prior to administration of the medicament if the needle shieldwhich normally covers the needle has been removed. Moreover,US2007/0191809 allows for the removal of the plunger postadministration, which could render it possible to reuse the syringe.

SUMMARY

In view of the above, a general object of the present disclosure is toprovide a medicament delivery device which at least mitigates theproblems of the prior art.

Hence, according to a first aspect of the present disclosure there isprovided a medicament delivery device for injection of a medicament,comprising: a housing having a distal end opening and a proximal endopening; a needle guard extending from the proximal end opening andmoveable relative to the housing from an extended position to aretracted position in which the needle guard is biased towards theextended position; an activation member extending from the distal endopening and movable relative to the housing from an initial position toa final position; final position locking means arranged to restrictmovement of the activation member relative to the housing when theactivation member is in the final position; and needle guard lockingmeans arranged to interact with the needle guard such that movement ofthe needle guard from the extended position to the retracted position isrestricted when the activation member is in the final position.

The words “distal end” and “proximal end” may be used in conjunctionwith any of the components of the medicament delivery device. In eachcase, “proximal end” refers to that end of the component which is theend of component in the direction in which the needle points, and“distal end” refers to the opposite end.

An effect which may be obtainable hereby is that the needle guard, whichis normally in the extended position relative the proximal end openingof the housing, covers the needle both prior to and after administrationof a medicament. Prior to administration, the needle guard is movablebetween the extended position and the retracted position in which theneedle guard is biased towards the extended position to protect theneedle and to protect from needle sticks until administration of themedicament. After administration, i.e. when the activation member is inthe final position, movement of the needle guard from the extendedposition is restricted. In this state, the needle guard covers theneedle at all times and prevents needle stick and reuse of themedicament delivery device. The activation member is also restricted tomove from its final position which provides additional protection fromreuse of the medicament delivery device. It furthermore renders it moredifficult to access the syringe after administration of the medicament.

According to one embodiment the activation member has a cutout and thehousing has an inner surface provided with a final position lockingmember arranged to engage the cutout when the activation member ispositioned in the final position.

Alternatively, the housing could comprise the cutout instead of theactivation member and the activation member could be provided with thefinal position locking member instead of the housing for engagement withthe cutout of the housing.

According to one embodiment the activation member has a blocking memberarranged to prevent movement of the needle guard from the extendedposition to the retracted position when the activation member is in thefinal position. Thereby, axial movement of the needle guard towards theproximal end opening can be prevented.

According to one embodiment the needle guard has an activation memberinteraction leg which is aligned with and facing the blocking memberwhen the activation member is in the final position and the needle guardis in the extended position.

According to one embodiment the housing has an inner surface providedwith a blocking member pressing tab arranged to push the blocking memberaway from the inner surface when the activation member is in the finalposition to align the blocking member with the activation memberinteraction leg when the needle guard is in the extended position.Thereby, the blocking member can be positioned to prevent the activationmember interaction leg, and thus the needle guard, to move towards theretracted position.

One embodiment comprises initial position locking means arranged tointeract with the needle guard and with the actuation member such thatmovement of the activation member from the initial position to the finalposition is restricted when the needle guard is in the extendedposition. Hence, administration of the medicament is prevented as longas the needle guard is in the extended position. Administration ofmedicament is allowed only when the needle guard is set in the retractedposition, i.e. when the medicament delivery device is in position toadminister the medicament.

One embodiment comprises a container holder having a tab, wherein theinitial position locking member comprises the tab, and wherein theactivation member has a cutout, wherein the tab is arranged to engagethe cutout in the initial position. The cutout of the activation membermay according to one variation be the same cutout which is arranged tointeract with the final position locking member of the housing.

According to one embodiment the needle guard has a container holder tabinteraction leg arranged to push the tab out from the cutout when theneedle guard is in the retracted position.

According to one embodiment the housing and the activation member havelocking means arranged to interact such that movement of the activationmember in a direction from the initial position to the final position isallowed, and movement of the activation member in the opposite directionis restricted.

According to one embodiment the final position locking member is a snapmember.

According to one embodiment the tab of the container holder is aresilient snap moveable towards the container holder.

According to one embodiment the activation member is a manual plungerrod.

According to a second aspect of the present disclosure there is provideda method of assembling a medicament delivery device according to thefirst aspect. The method comprises: a) arranging a needle guard and abiasing member in a housing; b) arranging a drug cartridge in thehousing; and c) arranging, via a distal end opening of the housing, theactivation member in the housing.

One embodiment comprises arranging a container holder in the housing,wherein the drug cartridge is arranged in the container holder.

According to one embodiment the needle guard is arranged in the housingfrom any of the distal end opening and a proximal end opening of thehousing.

Generally, all terms used in the claims are to be interpreted accordingto their ordinary meaning in the technical field, unless explicitlydefined otherwise herein. All references to “a/an/the element,apparatus, component, means, etc. are to be interpreted openly asreferring to at least one instance of the element, apparatus, component,means, etc., unless explicitly stated otherwise.

BRIEF DESCRIPTION OF THE FIGURES

The specific embodiments of the inventive concept will now be described,by way of example, with reference to the accompanying drawings, inwhich:

FIG. 1 is a perspective view of an example of a medicament deliverydevice;

FIG. 2 is an exploded view of the medicament delivery device in FIG. 1;

FIGS. 3a-b is a top view and a longitudinal section, respectively, of ahousing of the medicament delivery device in FIG. 1;

FIG. 4 is a perspective view of a needle guard of the medicamentdelivery device in FIG. 1;

FIG. 5 is a perspective view of an activation member of the medicamentdelivery device in FIG. 1;

FIGS. 6a-b are perspective views of a medicament delivery device in aninitial state;

FIGS. 7a-b are perspective views of a medicament delivery device in aninserted state;

FIGS. 8a-b are perspective views of a medicament delivery device in anstate when a drug injection has been performed;

FIGS. 9a-b show a medicament delivery device in a pulled out state; and

FIG. 10 is a flowchart describing a method of assembling the medicamentdelivery device in FIG. 1.

DETAILED DESCRIPTION

The inventive concept will now be described more fully hereinafter withreference to the accompanying drawings, in which exemplifyingembodiments are shown. The inventive concept may, however, be embodiedin many different forms and should not be construed as limited to theembodiments set forth herein; rather, these embodiments are provided byway of example so that this disclosure will be thorough and complete,and will fully convey the scope of the inventive concept to thoseskilled in the art. Like numbers refer to like elements throughout thedescription.

FIG. 1 depicts an example of a medicament delivery device 1 loaded witha syringe containing a drug and ready for use. The medicament deliverydevice 1 comprises a housing 3, an activation member 5, a cap 7 a, asyringe needle shield 7 b, a needle guard 9, and a label 11 withinformation of the drug contained in the medicament delivery device 1.The label 11 can for example be provided on an external surface of thehousing 3. The housing 3 may further have a transparent window 13 whichallows inspection of the drug prior to the administration thereof.

The housing 3 has a proximal end opening 3 a, a distal end opening 3 bopposite the proximal end opening 3 a and a through opening extendingfrom the proximal end opening 3 a to the distal end opening 3 b. Theactivation member 5 is coaxially arranged in the housing 3 and extendsfrom the housing 3 at the distal end thereof through the distal endopening 3 b. The activation member 5 is moveable relative to the housing3 from an initial position to a final position.

The activation member 5 is sleeve shaped and has a predetermined lengthdepending on the volume of medicament contained within the syringe. Theactivation member comprises an open and closed end

In FIG. 1, the activation member is in an initial position relative tothe housing 3. The initial position is the position in which theactivation member 5 is arranged prior to the injection of a drug, i.e.the position in which the activation member protrudes a predeterminedlength from the distal end opening 3 b of the housing and wherein saidpredetermined length may correspond to the stroke length for deliveringthe complete volume of medicament within the syringe. The activationmember 5 is in a final position when a maximal allowed portion of theactivation member 5 has been received by the housing 3, as will beillustrated in FIGS. 7-9. The activation member 5 is in the finalposition when the drug has been fully administered, i.e. in the positionin which the predetermined length of the activation member is positionedwithin the housing.

The medicament delivery device 1 further comprises final positionlocking means which are arranged to restrict movement of the activationmember 5 relative to the housing 3 when the activation member 5 is inthe final position. In the following, the final position locking meanswill be exemplified by a final position locking member 3 g of thehousing, as shown in FIG. 3b , and a corresponding cutout 5 b in theactivation member 5. The medicament delivery device 1 also comprisesneedle guard locking means arranged to interact with the needle guardsuch that movement of the needle guard 9 from an extended position to aretracted position is restricted when the activation member 5 is in thefinal position. In the following, the needle guard locking means will beexemplified by a blocking member 5 a of the activation member 5 and ablocking member pressing tab 3 h, as shown in FIG. 3b , on the innersurface of the housing 3.

FIG. 2 is an exploded view of the medicament delivery device 1. Inaddition to the components shown in FIG. 1, the exemplified medicamentdelivery device 1 comprises a container holder 15 i.e. a syringe holder,a spring 17, a drug syringe 19 having a needle and a stopper 21.

The needle guard 9 is coaxially arranged in the housing 3 and extendsfrom the housing 3 at the proximal end thereof through the proximal endopening 3 a. The needle guard 9 is moveable relative to the housing 3from the extended position to the retracted position in which the needleguard is biased towards the extended position by means of a biasingmember, which in the present example is the spring 17. The activationmember 5 and the needle guard 9 extend in opposite directions from thehousing 3. The activation member 5 has a larger cross-sectionaldimension than the needle guard 9, allowing the distal end portions ofthe needle guard to move within the activation member 5.

The housing 3 and the activation member 5 have locking means arranged tointeract such that movement of the activation member 5 in a directionfrom the initial position to the final position is allowed, and movementof the activation member in the opposite direction is restricted.According to the present example, the locking means of the housing 3 isdefined by a blocking member 3 c and the corresponding locking means ofthe activation member 5 is defined by a cutout 5 b. The blocking member3 c of the housing 3 hence prevents the removal of the activation member5 from the housing 3. It is envisaged that as an alternative hereto thehousing could be provided with the cutout and the activation membercould comprise the blocking member.

The exemplified housing 3 has a cutout 3 d at a side thereof. The cutout3 d locks or fixes the housing 3 to the container holder 15 which has acorresponding lateral leg 15 a which engages the cutout 3 d. There maybe several cutouts 3 d along the periphery of the housing 3 withcorresponding lateral legs 15 a protruding from the container holder 15.It should be noted that instead of the lateral leg 15 a engaging thecutout 3 d and thus fixing the container holder 15 to the housing 3, theend portions of the lateral legs could be integrated with the housing soas to form a single piece housing and container holder. In this case,the end portions of the lateral legs could for example be moulded to theinner surface of the housing during manufacturing, thus integrating thehousing and the container holder.

The needle guard 9 is in the extended position relative to the housing3. The extended position is the position in which the needle guardprotrudes a predetermined length from the proximal end opening 3 a ofthe housing and wherein said predetermined length may correspond to thelength for covering the needle from sight. The needle guard 9 is in aretracted position when a maximal allowed portion of the needle guard 9has been received by the housing 3, as will be illustrated in FIGS. 7-8.The needle guard 9 is in the retracted position when the needle isexposed to sight.

The activation member 5 comprises a blocking member 5 a at the proximalend thereof. According to the example in FIG. 2, the blocking member 5 ais a resilient leg extending at the proximal end of the activationmember 5. The blocking member 5 a is arranged to prevent movement of theneedle guard 9 from the extended position to the retracted position whenthe activation member 5 is in the final position. The activation member5 further has a cutout 5 b which is open in a direction facing theblocking member 5 a, i.e. the resilient leg. The cutout 5 b has threefunctions according to the present example. The first function of thecutout 5 b is to fix the activation member 5 in the initial position viainteraction with an initial position locking member of the containerholder 15 when the needle guard 9 is in the extended position. Thesecond function of the cutout 5 b is to fix the activation member 5 inthe final position via interaction with a final position locking memberof the housing 3, as will be described in more detail with reference toFIGS. 3a-b . The third function of the cutout 5 b is to interact withthe blocking member 3 c of the housing to prevent removal of theactivation member 5 from the housing 3.

The syringe 19, which contains the drug to be administered or injected,comprises a needle 19 a. Upon assembly, the syringe 19 is arranged inthe container holder 15 which is hollow. The needle shield 7 b, whichmay be a flexible needle shield (FNS) or a rigid needle shield (RNS), isarranged to receive the needle 19 a to protect the needle. The cap 7 acan be arranged on the needle guard 9 to cover the needle guard 9 andthereby provide robust protection of the needle 19 a for example duringtransport and storage of the medicament delivery device 1. The needleshield 7 b can be arranged to cover the needle 19 a. In particular, theneedle shield 7 b can be fixedly attached to the inside of the cap 7 ain such a manner that the needle shield 7 b is removed simultaneouslywith the cap 7 a.

The container holder 15 further has initial position locking means 15 barranged to interact with the needle guard 9 and with the actuationmember 5 such that movement of the activation member 5 from the initialposition to the final position is restricted when the needle guard 9 isin the extended position. According to the present example the initialposition locking means 15 b comprises a tab arranged to engage thecutout 5 b of the activation member 5 when the activation member 5 is inthe initial position, fixing the activation member 5 in the initialposition until the needle guard 9 is moved to the retracted position.The initial position locking means 15 b or tab of the container holder15 is a resilient snap moveable towards the container holder 15. Theinitial position locking means 15 b may extend in an inclined manner ina direction from the proximal end to the distal end of the containerholder 15.

The container holder 15 has a proximal end portion 15 d around which thespring 17 is arranged. When the medicament delivery device 1 isassembled, the spring 17 is arranged between the needle guard 9 and thecontainer holder 15. The spring 17 is tensioned when the needle guard 9is in the retracted position. In the retracted position the needle guardis thus biased towards the extended position.

The needle guard 9 has an activation member interaction leg 9 a. Theactivation member interaction leg 9 a is aligned with and facing theblocking member 5 a of the activation member 5 when the activationmember 5 is in the final position and the needle guard 9 is in theextended position, i.e. after injection when the needle 19 a has beenpulled out from the skin. The needle guard 9 further has a containerholder tab interaction leg 9 b adapted to push the initial positionlocking member 15 b, i.e. the tab, out from the cutout 5 b of theactivation member 5 when the needle guard 9 is in the retractedposition. The container holder tab interaction leg 9 b extends towardsthe cutout 5 b of the activation member 5 and is aligned with the cutout5 b and the initial position locking member 15 b.

FIG. 3a is a top view of the housing 3 showing its distal end, and FIG.3b is a longitudinal section of the housing 3 along lines A-A. In FIG.3b , a perspective view of a portion of the interior of the housing 3 isshown. The proximal end opening 3 a has a rim 3 e which retains theneedle guard 9 in the housing 3. In particular, the rim 3 e abuts ashoulder 9 c, shown in FIG. 4, of the needle guard 9 when the needleguard 9 is in the extended position. The housing 3 has an inner surface3 f provided with a final position locking member 3 g aligned with thecutout 5 b of the activation member 5 in a direction from the distal endto the proximal end of the housing 3. The final position locking member3 g is arranged to interact with the actuation member 5 such thatmovement of the activation member 5 is restricted when positioned in thefinal position. In particular, the final position locking member 3 g maycomprise or be defined by a tab or snap member. The tab or snap memberis according to one example wedge-shaped, wherein the tab or snap memberhas an inclined face forming a ramp in the direction from the distal endto the proximal end of the housing 3. From the other direction, i.e.from the proximal end to the distal end, the face adjacent the ramp facemay be essentially perpendicular to the internal surface 3 f. The finalposition locking member 3 g engages with the cutout 5 b of theactivation member 5 when the activation member 5 is in the finalposition. The final position locking member 3 g may bence efficientlyprevent movement of the activation member 5 once it has reached itsfinal position.

The inner surface 3 f is further provided with a blocking memberpressing tab 3 h protruding from the inner surface 3 f. The blockingmember pressing tab 3 h is aligned with the blocking member 5 a in adirection from the distal end to the proximal end of the housing 3. Theblocking member pressing tab 3 h is arranged to press the blockingmember 5 a, i.e. the resilient leg, of the activation member 5 away fromthe inner surface 3 f when the activation member 5 is in the finalposition. When the needle guard 9 is in the retracted position, theblocking member 5 a is pushed against the outer surface of theactivation member interaction leg 9 a because the cross-sectionaldimension of the needle guard 9 is smaller than the cross-sectionaldimension of the activation member 5. When the needle guard 9 is movedto the extended position the activation member interaction leg 9 a isretracted from below the blocking member 5 a. The blocking member 5 a istherefore pushed further away from the inner surface 3 f of the housingby the blocking member pressing tab 3 h until the blocking member 5 a isin level with the path of movement of the activation member interactionleg 9 a. In this position, the tip of the blocking member 5 a is alignedwith and faces the tip of the activation member interaction leg 9 a.Hence axial movement of the activation member interaction leg 9 a isrestricted when the needle guard 9 is in the extended position combinedwith the activation member 5 being in the final position.

The container holder 15 has lateral guiding elements 15 c which arearranged to interact with corresponding guiding elements 3 i in thehousing 3. The guiding elements 15 c of the container holder 15 could beprotruding tabs or slits, depending on the design of the correspondingguiding elements 3 i in the housing 3. According to the present example,the inner surface 3 f of the housing 3 is provided with guiding elements3 i which interact with the lateral guiding elements 15 c of thecontainer holder 15. Alignment of the housing 3 and the container holder15 may thereby be obtained in a simple manner when assembling themedicament delivery device 1. Especially, the guiding elements 3 i and15 c guide the lateral legs 15 a to the cutouts 3 d of the housing 3 forattachment of the housing 3 to the container holder 15.

FIG. 4 is a perspective view of the needle guard 9. The needle guard 9has a main body 9 d which is arranged to house the needle 19 a when theneedle guard 9 is in the extended position. The activation memberinteraction legs 9 a extend distally from the main body 9 d. Thecontainer holder tab interaction legs 9 b extend distally from theneedle guard 9 towards the activation member 5. The container holder tabinteraction legs 9 b have a longer longitudinal extension than theactivation member interaction legs 9 a. The main body 9 is provided witha shoulder 9 c. The shoulder 9 c can for example have a rectangularcross-section or a triangular cross-section. The shoulder 9 c may thusfor example be chamfered, defining a ramp in a direction from the distalend to the proximal end. Depending on the shape of the shoulder 9 c,arrangement of the needle guide 9 into the housing 3 may either beperformed from the distal end opening 3 b or the proximal end opening 3a of the housing 3 during assembly of the medicament delivery device 1.

FIG. 5 is a perspective view of the activation member 5. The activationmember 5 is preferably a manual rod. The activation member 5 has an openproximal end and a distal end 5 d which is closed. The cutout 5 b, whichmay be open or closed, has a proximal edge 5 b′ and a distal edge 5 b″opposite the proximal edge 5 b′. The proximal edge 5 b′ interacts withthe final position locking member 3 g in the final state. For example,the final position locking member 3 g of the housing 3, and inparticular the face adjacent the ramp face, may abut the proximal edge 5b′ when the activation member 5 is in the final position. The proximaledge 5 b′ also interacts with the blocking member 3 c of the housing 3in the initial position to prevent the activation member 5 to be removedfrom the housing 3. The distal edge 5 b″ interacts with the initialposition locking means 15 b in the initial state preventing theactivation member 5 to be moved to the final state when the needle guard9 is in the extended position. The exemplified activation member 5 has athrough slit 5 e and through opening 5 f on respective sides of theblocking member 5 a defining a leg and thereby rendering the blockingmember 5 a resilient. According to the present example, the cutout 5 bforms part of the through opening 5 f. It is however to be noted thatthe cutout could alternatively be an isolated through opening.

The activation member 5 may have a hollow interior comprising a plungerrod extending longitudinally from the distal end 5 d to the proximal endinside the activation member 5. The plunger rod may be arranged in adistal end opening of the syringe 19 and the syringe may be sealed bymeans of the stopper 21. Movement of the activation member 5 from theinitial position to the final position hence moves the plunger rod inthe syringe and allows for injection of the drug. Alternatively, theplunger rod could be a component that separate from the activationmember and forming part of the syringe. In this case, the activationmember could have a hollow interior allowing the reception of theplunger rod for enabling manoeuvring of the plunger rod.

The functioning of the medicament delivery device 1 will now bedescribed in more detail with reference to FIGS. 6-9. FIG. 6a is aperspective view of the medicament delivery device 1 in a default state,which is the state of the device 1 wherein the cap 7 a together with theneedle shield 7 b has been removed from the device.

The medicament delivery device 1 is loaded with a syringe containing adrug and is ready for use. The activation member 5 is in the initialposition A. The needle guard 9 is in the extended position B. Thus,movement of the activation member 5 towards the final position isrestricted.

FIG. 6b shows the medicament delivery device 1 with the housing removedto make visible internal components in the default state. It can be seenthat the initial position locking means 15 b, a snap member, extendsinto the cutout 5 b of the activation member 5 to restrict movement ofthe activation member 5 towards the final position. The container holdertab interaction leg 9 b of the needle guard 9 is aligned with theinitial position locking means 15 b. The container holder tabinteraction leg 9 b extends from the main body 9 d of the needle guard 9towards the initial position locking means 15 b which protrudes from thecontainer holder 15 in an inclined manner in a direction from theproximal end to the distal end of the container holder 15 into thecutout 5 b.

FIG. 7a is a perspective view of medicament delivery device 1 in a statein which the needle 19 a normally is inserted into an object such as apatient for administration of the drug. In this state, the needle guard9 is in the retracted state B′, in which the needle 19 a is emerged. Theactivation member 5 is still in the initial state A. The drug is at thispoint thus still fully contained in the syringe.

FIG. 7b shows the medicament delivery device 1 with the housing removedto make visible internal components in the state shown in FIG. 7a . Ascan be seen, by means of the movement of the needle guard 9 from theextended position B to the retracted position B′, the container holdertab interaction leg 9 b has moved in a direction from the proximal endto the distal end. By this movement, the initial position locking member15 b, which is resilient and in its normal state inclined in a directionfrom the proximal end to the distal end, has been pushed underneath thecontainer holder tab interaction leg 9 b of the needle guard 9. Hereby,the activation member 5 is released in the sense that it may now bemoved from the initial position A to the final position A′, as shown inFIG. 8 a.

FIG. 8a is perspective view of medicament delivery device 1 in a statewhen injection has been finalised but the needle 19 a is still insertedin the patient. The needle guard 9 is in the retracted position B′ andthe activation member 5 is in the final position A′. It can be notedthat the transparent window 13 is covered by the activation member 5.

FIG. 8b shows the medicament delivery device 1 with the housing removedto make visible internal components in the state shown in FIG. 8a .Although the housing 3 is removed, it can be seen that the blockingmember 5 a of the activation member is pushed away from the innersurface of the housing inwards in the medicament delivery device 1. Theblocking member 5 a is pushed inwards by the blocking member pressingtab 3 h, not shown in FIG. 8b . The blocking member 5 a rests on theactivation member interaction leg 9 a of the needle guard 9. The finalposition locking member 3 g, also not shown, of the housing 3 engageswith the cutout 5 b in the final position, restricting the movement ofthe activation member 5.

FIG. 9a is perspective view of medicament delivery device 1 in its finalstate when it has been pulled out from the patient. In this state theneedle guard 9 is again in the extended position B, which is obtaineddue to the biasing force of the spring 17. The activation member 5 is inthe final position A′.

FIG. 9b shows the medicament delivery device 1 with the housing removedto make visible internal components in the final state. Just as in FIGS.8a-b , the final position locking member of the housing engages with thecutout 5 b in the final position, restricting the movement of theactivation member 5. Since the needle guard 9 has a smallercross-sectional dimension than the activation member 5, the needle guard9 would be allowed to move to the retraced position B′ if the blockingmember 5 a was not pushed in a direction away from the inner surface ofthe housing. The blocking member 5 a is however pushed inwards by theblocking member pressing tab 3 h of the housing, blocking movement ofthe activation member interaction leg 9 a thus restricting axialmovement of the needle guard 9. The movement of the needle guard 9 ishence restricted when the activation member 5 is in the final positionA′.

FIG. 10 is a flowchart of a method of assembling a medicament deliverydevice such as medicament delivery device 1. In a step a) the needleguard 9 and a biasing member are arranged in the housing 3. The biasingmember may for example be a spring 17. The needle guard 9 and thebiasing member may be placed in the housing 3 from either the proximalend opening 3 a or the distal end opening 3 b. If the shoulder 9 c ischamfered as described above, the needle guard 9 may be inserted intothe housing 3 from the proximal end opening 3 a. Otherwise, the needleguard 9 is inserted into the housing through the distal end opening 3 b.In a step b) a drug cartridge, i.e. a syringe, is arranged in thehousing 3. The syringe is typically inserted from the distal end opening3 b of the housing 3. In a step c) the activation member 5 is arrangedin the housing 3. The activation member 5 is inserted into the housing 3from the distal end opening 3 b of the housing 3.

If the housing 3 and the container holder 15 are separate components,the container holder is inserted into the housing prior to step b). Ifthe housing and the container holder are an integrated unit, the syringeis placed in the integrated housing and container holder. The label 11can be arranged on the housing 3 before or after assembly of themedicament delivery device.

The medicament delivery device presented herein hence protects usersfrom needle sticks prior to and after administering a drug. The needleessentially only appears during the operation of injection of the drug.Moreover, the activation member and the needle guard are fixed relativethe housing after administration of the drug, rendering reuse of themedicament delivery device difficult. The medicament delivery device mayfor example be used for drug administration for the treatment ofdiabetes, rheumatism, or to treat growth hormone deficiency in children.The medicament delivery device may for example be manufactured ofplastic.

The inventive concept has mainly been described above with reference toa few examples. However, as is readily appreciated by a person skilledin the art, other embodiments than the ones disclosed above are equallypossible within the scope of the inventive concept, as defined by theappended claims. For example, instead of the final position lockingmeans being comprised of a final position locking member 3 g of thehousing and a corresponding cutout 5 b in the activation member 5, thehousing could be provided with a cutout and the activation member couldbe provided with a final position locking member, e.g. a snap. In thiscase, the cross-sectional dimension of the needle guard could be largerthan that of the activation member so that the activation member couldpartially be received by the needle guard. The initial position lockingmeans could be a resilient snap provided on the external surface of theactivation member and distal leg of the needle guard could be arrangedto interact with the initial position locking means to allow movement ofthe activation member when the needle guard is in the retractedposition. The needle guard locking means could be a snap memberextending from the container holder pushing the blocking member, e.g. aresilient leg, of the activation member towards the inner surface of thehousing, thus blocking the movement path of a corresponding leg of theneedle guard. Alternatively, the housing could instead of a blockingmember pressing tab be provided with a slot which extends along theinner surface of the housing from the distal end to the location of thetab according to the detailed example described hereabove and theblocking member of the activation member could be provided with a tabslideably arranged in the slot thus pushing the blocking member awayfrom the housing when the activation member is in the final position.

1. A device for injecting a medicament, comprising: a housing having adistal end opening and a proximal end opening; a needle guard; a biasingmember that biases the needle guard in a proximal direction; and anactivation member slidably positioned within the housing such that afirst portion of an outer surface of the activation member extendslongitudinally from an inside surface of the distal end opening when theactivation member is in an initial position, where during injection ofthe medicament the activation member is moved axially relative to thehousing in a proximal direction to a final position such that a secondportion of the outer surface extends longitudinally from the distal endopening, where the second portion is smaller than the first portion. 2.The device of claim 1, wherein the biasing member comprises a spring. 3.The device of claim 1, wherein the needle guard extends from theproximal end opening of the housing when in the extended position. 4.The device of claim 1 further comprising a final position lock disposedon an inner surface of the housing and configured to restrict movementof the activation member relative to the housing when the activationmember is in the final position.
 5. The device of claim 4, wherein theactivation member has an edge, and the final position lock engages theedge when the activation member is in the final position.
 6. The deviceof claim 1, wherein the activation member has a blocking memberconfigured to prevent movement of the needle guard when the activationmember is in the final position and the needle guard is in an extendedposition relative to the housing.
 7. The device of claim 6, wherein theneedle guard has an activation member interaction leg that is alignedwith and faces the blocking member when the activation member is in thefinal position and the needle guard is in the extended position.
 8. Thedevice of claim 1 further comprising an initial position lock configuredto interact with the activation member such that movement of theactivation member from the initial position to the final position isrestricted when the needle guard is in an extended position relative tothe housing.
 9. The device of claim 8 further comprising a containerholder, wherein the initial position lock comprises a tab on thecontainer holder, the activation member has an edge, and the tab isconfigured to engage the edge in the initial position.
 10. The device ofclaim 9, wherein one end of the biasing member is operatively engagedwith the container holder and an opposite end of the biasing member isoperatively engaged with the needle guard.
 11. The device of claim 9,wherein the tab on the container holder is a resilient snap movabletoward the container holder.
 12. The device of claim 9, wherein thecontainer holder is arranged in the housing and is configured to hold amedicament cartridge.
 13. The device of claim 4, wherein the finalposition lock is a snap member.
 14. The device of claim 1, wherein theactivation member is a manual plunger rod.
 15. The device of claim 1,wherein the housing and the activation member have interacting locksthat allow movement of the activation member in a direction from theinitial position to the final position and restrict movement of theactivation member in an opposite direction.
 16. The device of claim 1further comprising a needle guard lock configured to interact with theneedle guard such that movement of the needle guard is restricted whenthe activation member is in the final position.
 17. A method ofassembling a device for injecting a medicament, the method comprising:arranging a needle guard within the housing such that it is operativelyengaged with a biasing member, where the housing has a distal endopening and a proximal end opening and where the needle guard isarranged such that the needle guard extends from the proximal endopening; and arranging, via the distal end opening of the housing, anactivation member in the housing such that the activation member isslidably positioned within the housing such that a first portion of anouter surface of the activation member extends longitudinally from aninside surface of the distal end opening when the activation member isin an initial position, where during injection of the medicament theactivation member is moved axially relative to the housing in a proximaldirection to a final position such that a second portion of the outersurface extends longitudinally from the distal end opening and where thesecond portion is smaller than the first portion,
 18. The method ofclaim 17 further comprising arranging a container holder in the housing,wherein the container holder is configured to hold a medicamentcartridge and is operatively engaged with the biasing member thatcomprises a spring.
 19. The method of claim 17, wherein arranging theneedle guard in the housing comprises arranging the needle guard in thehousing from the distal end opening of the housing or the proximal endopening of the housing.
 20. The method of claim 17, wherein a finalposition lock is disposed on an inner surface of the housing andconfigured to restrict movement of the activation member relative to thehousing when the activation member is in the final position.